Excess Electron Transfer through DNA Duplexes Comprising a Metal-Mediated Base Pair.

Excess electron transfer through one set of DNA duplexes comprising either one or two metal-mediated thymine-Hg -thymine base pairs was studied. Towards this end, the metal-mediated base pair(s) were introduced between an artificial nucleoside bearing a N,N,N',N'-tetramethyl-1,5-diaminonaphthalene derivative (dN, acting as a photoinducible electron donor) and 5-bromo-2'-deoxyuridine (dB, acting as an electron acceptor). Upon one-electron reduction, dB loses a bromide ion.

A metal-mediated base pair that discriminates between the canonical pyrimidine nucleobases.

A nucleoside analogue comprising the ligand 1-imidazo[4,5-][1,10]phenanthroline () was applied to develop a molecular beacon capable of discriminating the canonical nucleobases cytosine and thymine. The beacon is based on the formation of a stable Ag-mediated base pair between and cytosine, whereas the presence of Ag strongly destabilizes nucleic acids comprising an artificial base pair between and thymine. Metal-mediated base pair formation was investigated by temperature-dependent UV spectroscopy and CD spectroscopy and complemented by extensive DFT calculations.

Sequence-Dependent Duplex Stabilization upon Formation of a Metal-Mediated Base Pair.

An artificial nucleoside surrogate with 1H-imidazo[4,5-f][1,10]phenanthroline (P) acting as an aglycone has been introduced into DNA oligonucleotide duplexes. This nucleoside surrogate can act as a bidentate ligand, and so is useful in the context of metal-mediated base pairs. Several duplexes involving a hetero base pair with an imidazole nucleoside have been investigated.